Medications are often dispensed to a patient via a dispensing device, such as a syringe. The syringe generally includes a barrel which holds the medication, a needle attached to one end of the barrel to inject the medication into the patient, and a plunger slideably received within the other end of the barrel to push the medication out of the barrel and into the needle.
Many medications are packaged in prefilled syringes. In a prefilled syringe, the syringe barrel is filled with a full dose of the medication. The needle of the prefilled syringe is typically covered and/or replaced with a safety cap. To dispense the medication, the needle is attached to the end of the barrel and/or the safety cap is removed from the needle and the needle is inserted into the patient. The patient or caregiver slides the plunger through the barrel of the syringe until all of the medication is injected.
There are circumstances in which the patient does not need, or should not receive, a full dose of the medication in a prefilled syringe. For example, when a patient is starting a new medication, a doctor may recommend beginning with a partial dose to help the patient adapt to the medication. This approach is known as titration. To administer a partial dose, the patient is instructed to partially slide the plunger through the barrel. The syringe barrel may include graduated markings which the patient may use as a reference when dispensing a partial dose.